Cash Flows (Summary of Non-Cash Activities and Other Supplemental Data) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Non-Cash Investing and Financing Activities:
Finance lease additions	$ 14,260	$ 0
Capital expenditures incurred but not yet paid	2,105	1,659
Supplemental Data:
Cash interest paid	91,940	104,698
Income taxes paid, net	$ 60,335	$ 121,110